physiology: lung mechanics Flashcards Preview

semester 2 SF > physiology: lung mechanics > Flashcards

Flashcards in physiology: lung mechanics Deck (13)
Loading flashcards...
1
Q

Three different pressure considerations important in

ventilation

A
atmospheric (barometric) pressure
intra-alveolar pressure (intrapulmonary pressure)
intrapleural pressure (intrathoracic pressure)
2
Q

Atmospheric Pressure
pressure at sea level….
decreases when…

A

760mm Mg

as altitude increases

3
Q

Intra-alveolar Pressure
what is it
it varies with

A

pressure of air in alveoli (opened system)

phase of respiration
-during INSPIRATION = negative(IAP atmospheric pressure)

4
Q

what drives ventilation

A

•Difference between P(alv) and P(atm)

5
Q

Intrapleural Pressure
what
always…

A

-pressure inside pleural sac (closed system)

-less than Palv
negative under normal conditions at rest

6
Q

what does FRC stand for

what does it mean

A
  • functional residual capacity

- volume of air in lungs in between breathes …..Palv = Patm (2.2L)

7
Q

Factors determining intra-alveolar pressure:

A
  • quality of air

- volume of aveoli

8
Q

Inspiration:

A

lungs expand , aveolar volume increases

  • alveolar pressure ↓
  • pressure gradient is : air into lungs
  • quanity of air in alveoli rises
  • alveolar pressure↑
9
Q

expiration

A

lungs recoil , alveolar volume decreases

  • alveolar pressure ↑
  • pressure gradiant is lungs to air
  • quanity of air in aveoli ↓
  • alveolar pressure ↓
10
Q

Respiratory Muscle Activity During Inspiration

A

contraction of diaphragm and external intercostal muscles

elevation of rib cage

11
Q

Respiratory Muscle Activity During Expiration

A

contraction of internal intercostal muscles and abdominal muscles

12
Q

Factors Affecting Pulmonary Ventilation

A

lung compliance- lung expandability , less compliant lungs are more work required for inflation …… (affected by elasticity and tension of lungs)

Airway Resistance….. affected by passive forces, contracile activity of smooth muscles and mucus excretion( increased by pathologies)

13
Q

Work of breathing is increased in the following situations:

A

pulmonary compliance ↓
recoil elasticity ↓
airway resistance ↑